1. Field of the Invention
The present invention relates to an apparatus for reading and digital processing of colour images comprising a group of pluralities of elements for reading the individual pixel associated with the primary colours of the image for generating corresponding reading signals, and comprising reading mode selection means for selection for monochrome output the reading signals generated by a predetermined one of said pluralities of elements, the group of pluralities of elements being operable to control a colour indication circuit for indicating the presence of any colour in the image, the selection means being capable of enabling that circuit to output the colour indication in association with the reading signal generated by the predetermined one plurality of elements.
2. Description of the Related Art
Various apparatuses for reading multi-colour images are known, including filters which are associated with the various colours and which are rendered active sequentially for reading the corresponding colours.
However, on the one hand these apparatuses are capable of encoding the individual colours only in a binary mode, so that it is not possible to encode half-tones, while on the other hand they must be set up on each occasion for making a selection between reading in black and white and reading in colours.
U.S. Pat. No. 4,554,594 of the present assignee also discloses an apparatus for reading documents with monochrome images, in which encoding of the pixels is effected selectively in a binary mode when dealing with line images (characters of graphics) or a multi-level mode of greys when dealing with half-tone images. However that apparatus is not capable of effecting selection at a plurality of levels of encoding when reading colour images.